Safety and Effectiveness of No-touch Technique for Ascending Aorta in MICS-CABG

STATUS OF THE STUDY: Coronary Artery Bypass Grafting (CABG) surgery and Percutaneous Coronary Intervention (PCI) are important methods to address myocardial ischemia in coronary artery disease. CABG surgery, with its internal mammary artery bridging, can achieve a patency rate of more than 90% at 5 years after the procedure, which is currently the gold standard for the treatment of coronary artery disease. Although with the development of drug-eluting stents, coronary spinning mill technology and FFR technology, the incidence of mid- and long-term major adverse cardiovascular and cerebrovascular events (MACCE) of PCI treatment has been greatly reduced, CABG surgery is still the first choice for patients with complex coronary artery disease, left main stem disease and diabetes mellitus and other high-risk patients. However, traditional CABG surgery requires splitting the sternum, which is highly traumatic compared with PCI treatment, and carries a high surgical risk for patients with advanced age and comorbidities, as well as the risk of non-healing of the sternum. Minimal Invasive Cardiac Surgery-Coronary Artery Bypass Grafting surgery (MICS-CABG surgery) can reduce surgical trauma, surgical blood transfusion, and shorten postoperative hospitalization due to the avoidance of sternum injury.

Due to space constraints, MICS-CABG surgery cannot apply a proximal anastomosis to the ascending aorta and requires the use of a special sidewall clamp to clamp the ascending aorta, which poses two potential risks: 1. In patients with calcification and thickening of the ascending aorta, clamping of the ascending aorta may cause rupture of the intimal plaque and dislodgement, which can lead to the risk of cerebral infarction and peripheral arterial embolism; 2. minimal incision In bypass surgery, the proximal anastomosis of the ascending aorta has a very low tolerance rate. Due to the deep location of the ascending aorta, the surgical field and operating space are limited, and the suture is extremely difficult, if the anastomosis process occurs in the case of vascular tear, anastomotic leakage, or dislodgement of the sidewall clamp, it will cause serious uncontrollable aortic bleeding, which may endanger the patient's life in a short period of time.

SIGNIFICANCE: The optimization of the MICS-CABG surgical protocol through this topic reduces the surgical risk and removes the obstacles for the promotion of this technology.

In order to solve the problem of proximal anastomosis of MICS-CABG surgery in patients with calcification of the ascending aorta and to reduce the difficulty and risk of surgery. In 2020, our center began to explore the minimally invasive bypass surgery of ascending aorta non-touch (No-touch) technology, which refers to the bypass surgery without any manipulation of the ascending aorta, the proximal anastomosis of the bridge vessel in the axillary artery, through the first intercostal space of the bridge vessel to the thoracic cavity for the distal continuation of the anastomosis. The advantages of this technique are: 1) avoiding ascending aortic manipulation eliminates the risk of cerebral infarction and peripheral arterial embolism caused by plaque dislodgement from the ascending aorta; 2) the axillary artery rarely exists in calcification, and the vascular condition is good; 3) the axillary artery is simple to reveal, with plenty of room for maneuvering, and it can be anastomosed under direct vision, which greatly reduces the difficulty of the procedure, and if the anastomosis bleeds after the completion of the anastomosis, the bleeding is simple to stop, which decreases the risk of surgical manipulation.

This study will evaluate the safety and efficacy of this technique in a prospective cohort study. If the safety and efficacy of this technique are confirmed to be good, it will greatly expand the indications of this cutting-edge technique of MICS-CABG, optimize the surgical plan, reduce the surgical difficulty and shorten the learning curve.

Inclusion criteria

• Patients with angina pectoris who experience functional limitations in daily life and work despite conservative medical treatment and who require coronary artery bypass grafting surgery, as confirmed by coronary angiography, are eligible for enrollment.
• Patients with calcification of the ascending aorta, as confirmed by CT, who are not suitable for sidewall clamping are also eligible for enrollment.

Exclusion criteria

• The patient presents with an old, large myocardial infarction with no surviving myocardium, as evidenced by both isotope and echocardiographic imaging. This is a group of patients who are prone to complications, including significant cardiac enlargement, a cardiothoracic ratio greater than 0.75, an ejection fraction (EF) less than 30%, a left ventricular diameter (LVDd) greater than 70mm, the presence of a left ventricular ventricular wall tumor, or severe arrhythmia. Intraoperative hemodynamic instability;
• Valve surgery or other intracardiac surgery at the same time;
• Patients expected to undergo extracorporeal circulation surgery;
• Poor myocardial infarction conditions, extensive lesions, distal or full diffuse stenosis, or lumen diameter less than or severe calcification that cannot be anastomosed.
• Previous open heart surgery.
• Patients with preoperative hemodynamic instability requiring emergency surgery.
• Other conditions include terminal malignant tumors, uncontrollable infections, bleeding, persistent progressive degenerative systemic diseases, severe brain injuries, and multiple organ failure. Additionally, other significant organ function serious impairments, such as severe liver function impairment, severe heart failure, or cardiogenic shock, may also be considered contraindications. Inability to tolerate surgery may also be considered a contraindication.
• The participant declines to take part in this study.